VERY NICE to have water and a drain at your tank stand!!! Only thing I am wondering about is where is the stand pipe/floor drain going? If it is going into sewer line you will need a p/s trap in the drain line to prevent sewer gas from entering the house! If it is just under the house you could cause a mold/mildew problem if you do a lot of water changes or the humidity is high in your area.
Other than that everything looks great! MAN I WISH I had that much room under my house!!! We have less than half that much, so there is no way my broke back butt is squeezing under there! LOL
You have picked out some very nice drift wood pieces too! The plants look nice and healthy too! Did you get them locally? If so it must be nice to have a LFS with plants a large drift wood that nice!
Anyway have fun with the 75g, and all the excitement that comes with beginning a new tank!